The present invention relates to an electrical apparatus or the like provided with a battery which can be used by repeating charge and discharge and more particularly to an electrical apparatus or the like capable of determining a failed state of a battery.
Power is supplied to various electrical apparatuses such as an information terminal unit represented by a notebook-type personal computer (notebook PC), a PDA (Personal Digital Assistant), an MD (Mini Disk), and a video camera not only directly from a commercial power source but also from a battery (such as storage battery, secondary battery, or battery) which can be used many times while repeating charge and discharge. The battery uses a nickel-hydrogen battery or a nickel-cadmium battery that has a comparatively large capacity and is inexpensive. Moreover, a lithium-ion battery having a high energy density for unit weight compared to a nickel-cadmium battery and a lithium-polymer battery using a solid polymer instead of using a liquid electrolyte are used.
In the case of the battery representing the nickel-hydrogen battery, nickel-cadmium battery, lithium-ion battery, and lithium-polymer battery, the operating time is shortened when the service life of the battery expires. Therefore, users have a strong request for accurately knowing the service life of the battery. Therefore, there are some conventional electrical products each of which is constituted so as to show a state of a battery to users by displaying the data for the voltage, current, and capacity (%) of the battery.
However, conventional display of the voltage (V), current (A), and capacity (%) of a battery is only display of the basic data for the battery. Therefore, a user cannot determine whether a battery has a trouble and its guarantee period expires only from the basic data.
Moreover, when a user feels that the operating time of a battery is shortened, the user cannot determine whether the operating time is shorted due to a trouble of the battery or because battery is used after its guarantee period expires. Therefore, it is difficult for the user or a company receiving an inquiry from the user to take correct measures.
The present invention is made to solve the above technical problems and its object is to accurately determine whether a unit having a battery for supplying power to the body while repeating charge and discharge has a failure in the battery.
It is another object of the present invention to determine whether the guarantee period of a battery expires and take proper measures.